Effect of Probiotics on Doxycycline Disposition in Gastro-intestinal Tract of Poultry

Poultry feed is often supplemented with probiotics in order to improve disease resistance and growth performance and to decrease undesirable effects of antibacterial therapy. Therefore this study was designed to evaluate the effect of probiotics such as Lactobacillus brevis, L. plantarum and L. bulgaricus on pharmacokinetics of doxycycline in healthy DUC broiler chickens. The treatment with doxycycline at a dose of 10 mg/kg body weight started on the 15 day after hatching for 5 days via drinking water. The probiotics treated group received Lactobacillus strains for 15 days, 5 days after hatching. Treatment with probiotics did not lead to statistically significant differences in serum concentrations of doxycycline between both groups of chickens. The value of Cmax was significantly higher in the liver of doxycycline + probiotics treated chickens (0.23±0.1 μg/g) than in doxycycline-treated group (0.19±0.17 μg/g). The same tendency was observed in the jejunum of both groups of animals suggesting favourable results in the cure of bacterial diseases of the gastrointestinal tract of poultry.The selected dose was appropriate for treatment of infections caused by pathogens with MIC < 0.25 μg/mL irrespective of antibiotic administration alone or in combination with probiotics. The simultaneous treatment of chickens with probiotics and doxycycline did not entail changes in the dose regime of the antibiotic.